A conventional conversion element usually comprises silicone as matrix material in which the phosphor is present in an embedded state. However, silicone demonstrates poor heat conductivity, which causes the phosphor to heat up more intensely during operation and thus become less efficient. In addition, the refractive index of silicone equals approximately 1.4 and perceptibly differs from that of garnet phosphors, for example, the refractive index of which equals approximately 1.8. This difference leads to a stronger scattering, in particular if very small phosphor particles are embedded. This fine portion has thus previously been removed from the powder by fractionation.
A problem addressed by the invention is to provide a conversion element that has improved properties. In particular, the conversion element should demonstrate high heat conductivity. In particular, the conversion element should have a refractive index that is adjusted to the refractive index of a phosphor embedded in the conversion element.
Another problem addressed by the invention is to provide a component that is particularly stable and can in particular be produced at temperatures below 400° C.
In particular, any temperature-sensitive phosphor embedded in the conversion element should not be damaged during the production of the component.
A further problem addressed by the invention is that of, where possible, embedding all known various types of phosphor in a matrix material, in order to thus configure any desired color of light. That is an advantage compared with a conversion ceramic known from prior art, which can only be produced in specific colors of light. A combination of conversion ceramic, or of a conversion element and a phosphor embedded in a glass composition or a glass as matrix material, also allows the color spectrum of the conversion ceramic or of the conversion element to be advantageously expanded. This requires a matrix material in the conversion element, which does not undergo chemical reactions with any of the phosphors during the embedding process, which could involve a degradation of the phosphors. This property is strongly dependent on the composition of the matrix material, which is why only selected matrix materials are suitable.